Pump with flexible impeller and flexible annular cam



A. A. MCCRAY April 19, 1960 PUMP WITH FLEXIBLE IMPELLER AND FLEXIBLE ANNULAR CAM Filed Dec. 26, 1956 2 Sheets-Sheet 1 ALA/VA Q McCk4y,

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A. A. M CRAY April 19, 1960 PUMP WITH FLEXIBLE IMPELLER AND FLEXIBLE ANNULAR CAM Filed D60. 26, 1956 2 Sheets-Sheet 2 Unitd States l atent iice PUMP WITH FLEXIBLE IMPELLER AND FLEX- IBLE ANNULAR CAM Alan A. McCray, North Hollywood, Caliti, assignor to Jahsco Pump Company, Burbank, Calif., a corporation of California Application December 26, 1956, Serial No. 630,599

2 Claims. (Cl. 103-117) The present invention relates in general to pumps and, more particularly, to a pump having an impeller provided with flexible radial vanes adapted to be flexed by a cam incorporated in the pump to produce the necessary pumping action, a primary object of the invention being to provide a pump having an improved cam for this purpose.

Still more particularly, the invention contemplates a flexible-vaned pump of the concentric type, the impeller in a pump of this type being mounted for rotation about the axis of a cylindrical impeller bore and the vane flexure necessary to achieve a pumping action being produced by a cam located in the impeller bore at one side thereof, between and overlapping the inlet and outlet ports of the pu p A pump of the concentric type has numerous adv a- 568 over a pump of the eccentric type, wherein the impeller is mounted for rotation about an axis spaced from and parallel to the axis of the impeller bore to achieve the necessary vane fiexure, since all of the bores in the housing of a pump of the concentric type, including the impeller bore, bearing bores, and the like, are coaxial. However, the aforementioned cam required by the concentric type of pump to produce the necessary vane flexure has presented manufacturing difliculties prior to the present invention. Heretofore, flexible-vaned pumps of the concentric type have utilized a cam in the form of a machined insert mounted in the impeller bore at one side thereof between and overlapping the inlet and outlet ports, the angular or circumferential extent of such cam insert being considerably less than 180 degrees. Due to the fact that the radius of the internal peripheral wall of the cam varies circumferentially in the vicinities of the inlet and outlet ports to produce the desired vane fiexure, machining such an insert in accordance with prior practice presents troublesome problems. For example, it is difiicult to provide the internal wall of such a machined insert with a smooth contour for engagement by the blades or vanes of the impeller. It is also very difiicult to provide the internal wall of such a machined cam insert with the contour necessary to produce smooth and quiet operation. These and various other difliculties encountered with machined cam inserts are eliminated by the present invention, which is an important feature thereof.

A fundamental object of the invention is to provide a cam for a flexible-vaned pump of the concentric type which merely comprises a flexible, sheet metal annulus inserted into the impeller bore and formed to provide the desired circumferentially varying internal radius in the vicinities of the inlet and outlet ports. Such a sheet metal annular cam may be die formed to provide the desired internal contour accurately and easily, which is an important feature of the invention. Since sheet metal stock is a relatively inexpensive starting material, and

Patented Apr. 19, 1960 since sheet metal stock may be die formed inexpensively, as compared to machining other stock, the present invention greatly reduces the cost of cams for flexible vaned pumps, which is an important feature.

Since the sheet metal annular cam is formed to provide the internal peripheral wall thereof with a reduced radius intermediate the inlet and outlet ports, the external peripheral wall of the annular cam is spaced inwardly from the peripheral wall of the impeller bore between the inlet and outlet ports. An important object of the invention is to secure the annular cam in place in the impeller bore by means of an elastomeric spacer block inserted between the external peripheral wall of the annular cam and the peripheral wall of the bore in the region between the inlet and outlet ports, this elastomeric block being secured to the housing of the pump.

Another object is to provide a flexible, sheet metal annular cam in the formof a ring split at a point opposite the region of minimum internal radius, the annular cam of the invention thus being similar to an ordinary split piston ring. The elastomeric spacer mentioned is located adjacent the region of minimum internal radius of the annular cam and serves to lock the annular cam in place in the annular bore with the longitudinal or longitudinally extending ends of the split annular cam in abutment, thereby rendering the internal peripheral wall of the annular cam a continuous annular surface.

An object in connection with one embodiment of the invention is to provide a pump wherein the inlet and outlet ports in the housing are formed in the peripheral wall of the impeller bore and wherein the annular cam and the elastomeric spacer are provided with inlet and outlet ports respectively registering with the inlet and outlet ports in the housing. With this construction, the elastomeric spacer mentioned serves as a sealing means for preventing fluid leakage between the inlet and outlet ports in the housing through the space between the external peripheral wall of the annular cam and the peripheral wall of the impeller bore, ,which is an important feature.

An object in connection with another embodiment is to provide a pump wherein the inlet and outlet ports in the housing are formed in an end wall thereof, there being no ports through the annular cam and the elastomeric spacer in this embodiment.

Another object is to circumferentially locate the inlet and outlet ports in either the peripheral wall of the hous ing or the end wall thereof at the vane-flexing ramps formed by the transitions between the minimum internal radius of the annular cam and the maximum internal radius thereof.

The foregoing objects, advantages, features and results of the present invention, together with various other ob jects, advantages, features and results thereof which will be quite evident to those skilled in the pump are in the light of this disclosure, may be attained with the exemplary embodiments of the invention described in detail hereinafter and illustrated in the accompanying drawings, in which:

Fig. 1 is a transverse sectional view of a pump which embodies the invention;

Fig. 2 is an exploded perspective view of a flexible, sheet metal annular cam of the invention and of means of the invention for retaining the cam;

Fig. 3 is a side elevational view of another pump which embodies the invention; and

Fig. 4 is a transverse sectional view taken along th arrowed line 44 of Fig. 3.

Referring to Figs. 1 and 2 of the drawings, the numeral although-they may have other configurations.

ample, each of the ports 24 and 26 may comprise a plurality of circumferentially extending slots.

. inlet and outlet ports 14 and 16. inlet and outlet ports 14 and 16 and in the region of the designates a pump housing which is provided with a cylindrical impeller bore 12 and circumferentially spaced ports 14 and 16, the latter being formed in the peripheral wall 18 of the impeller bore in this embodiment. For the direction of impeller rotation hereinafter considered, the port 14 acts as an inlet port and the port 16 acts as an "outleb'port and the ports -14-and -16 will henceforth-be termed-inletand outlet ports for convenience.

Within- "the impeller-bore 12 is a-flexible,- sheet metal, annular cam' 20-in the form of a split ring,'the1 annular cam-having-longitudinal, i.e., longitudinally extending, ends ZZ-disposedin abutting relation. The annular cam 20 is provided with inlet and outlet ports 24 and-26 therethrough 'which register with the inlet andoutlet ports Hand 16, respectively. In the particular construction'illustrated, the inletand outlet ports 24 and 26 in the annular cam Zilareshown'as simple circular ports,

For ex- The annular cam v20 is provided .with circumferentially extending segments 28 .whichareseated against the pe- .ripheral. wall 13 ofthe impeller bore 12 and which have a maximum internal radius relative to the axis, 30, equal to or slightlyless than the radius of the pump impeller described hereinafter.

throughout the major circumferential distance between the In the regions of the minor circumferential distance between these ports,.the annular cam. 21 is spaced from the peripheral wall 18 of the impeller. bore 12. In the region of'the minor circumfereutialdistance between the inlet and outlet ports 14 and .16, the an'nularcani 20 provides a circumferentiallyextending segment 32 of minimum internal radius relative to the axis 30, the internal radius of the segment 32 preferably beingconstantthroughout the region of the minor circumferential spacing between the ports. At the ports Y24 and 26, the annular cam 20 is provided with circumferentially extending transitional segments or ramps 34- and 36 of radii varying circumferentially from the minimum adjacentthe segment 32 to the maximum adjacent the segment 28. The configurations of the internal peripheral walls of the transitional segments 34 and 36 are such as to provide the entire internal peripheralwallof 1 theannular cam with a smooth'contour.

'Disposed in the space between the housing .10and the segments 32,. 34.ancl 36,.and engaging the peripheral wall 18 of the impeller bore 12.and the external peripheral notchesi64 and 66 registering with:the ports 14 and. 16,

respectively, and with the ports 24- and 26, respectively. The elastomeric block38 serves to retain theannular cam 20 in the impeller bore 12 in its proper position and closes anygapbetween the longitudinal ends 22 of the annular cam bylbringing such ends into abutting; relation. Also, .in the embodiment under consideration, the elastomeric block 38 acts as a sealing means for preventing. ,fluid leakage between the inlet and outlet ports 14 and:16 by inlet and outlet ports 14 and 16, which is an important feature.

".Mounted withinthe annular cam 20'forrotation about the axis'30 of the impeller boreIZ-is an-eIastQmeric im- .pellelr lfil'r havingsal'iub 46 provided with fiexible radial vanes or blades 48 engagingr-the-internalperipheralWall ofthefannular cam. :Molded into theshub46 ofthe impeller 44 is an insert 50 which is telescopedovera 81131 052 andwhich is keyed thereto at 5 4.

The segments 28 ofmaximum internal radius wextend circumferentially substantially walls of these segments, 18 an elastomenc spacer or block .38 havingmolded thereinto anut 40 to receive a screw 42 threaded. through the housing 16, and having .therein in said"annular cam about the axis of said bo're, .said

in "the-clockwise directiomthe vanes 48 unflex'as they move along the transitional segment 34 of the annular cam 20 into engagement with the segment 28 of maximum internal radius, thereby enlarging the intervane spaces to draw fluid thereinto through the inlet ports 14 and 24. As the vanes 48 move along the transitional segment 36 into engagement with the segment 32 of minimum radius, the vanes are flexed to decrease the volumes of theintervanespaces, thereby discharging fluid-therefrom through the outlet ports26- and 16.

As will be apparent, the annular cam 20 can be die formed readily and inexpensively from sheet metal'stock, the cost of: the cam 20beingmuch less than the cost of prior machined cams. Also, it is possible to provide the sheet metal cam 24} with a smooth internal contour designed for quiet operation. Further, since the cam 20 is an annulus, wearis confined to thecam and to the impeller 44, which elements can readily be replaced, there being no wear of the housing 10.

Referring .now to'Figs. Band 4, various components ofthe embodiment illustrated therein correspond to. certain componentsofthe embodiment of Figs. 1 and land are designated by the samereferencenumerals plus 100.

The embodiment of Figs. 3 and 4 diifers in that the inlet andoutlet-portsu114 and.116 are'located-in an end wall 169 of the impeller bore 112, instead of in the peripheral wall 118 thereof, thereby making ports in the annular cam 120 andthe elastomeric spacer 138 unnecessary. It

:isthought that the structure and operation of this embodimentwill be apparent in the light of the descriptionxof the structure and operation-of the embodiment of Figs. 1 and 2.

Although exemplary embodiments of the invention have been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporatedtherein without departing from thespirit of the 'inventionas defined by um relativetoithe axis of said bore, said internal radius being a minimum between said inlet and outlet ports and progressively increasing adjacent said inlet and outlet ports, there being a space between the external peripheral wall of said annular cam and the peripheral wall of said bore between and overlapping said inlet and outlet ports, the radial dimension of said space being amaximum between said inlet andoutlet ports to provide said .minimum internal radius therebetween andprogressively decreasing adjacent said inlet and .outlet ports to provide said progressively "increasing internal radius there adjacent, said annular cam being a split cam having abuttable ends;an e'lasto'meric spacerin said space and extending radially from the external peripheral Wall of said annular cam "to the peripheral" wall' of said "impeller bore, said spacer providing 'a fluid-tightseal between said-annular ca'm andthe"peripheral .wallof' said impeller. bore between said in'let'and outlet ports and rhold'ingthe abuttable ends of. said annulancam inabutting relationpand flexible vanes engaging the. internal.peripheral'. wall of said annular cam.

2. Apump as set forth in claim 1 wherein said abuttable endsof saidannular'cam which are held 'in abutting i relation "by said spacer arediametrically opposite saidspacer.

. {References on following page) maspao 2 1 5 V 6 References Cited in the file of this patent 2,676,545 Barr Apr. 27, 1954 UNITED STATES PATENTS ami i 720,334 Michael Fcb. 17, 19 2:816:513 WatS0l1 1:: 1);. 17, 1951 763,525 Van Beresteyn June 28, 1904 5 1,322,764 Crago Nov. 25, 1919 2,465,887 Larsh Mar. 29,1949 FOREIGN PATENTS 2,659,313 Carson Nov. 17, 1953 807,977 Germany July 9, 1951 

